1. Field of the Invention
The present invention relates to the purification of organic sulfonates, and particularly organic ether sulfonates.
2. Description of the Prior Art
Organic sulfonates such as organic ether sulfonates are becoming increasingly important due to their use in liquid detergents, particularly in the preparation of relatively salt-free detergents having good solubility characteristics. Even more recently, the compounds of this general type have been found to be useful materials when employed as surfactants for enhanced oil recovery processes.
In many instances the process of choice used in making ether sulfonates often results in a product having impurities present which cannot be tolerated in view of many contemplated end uses of such impure products. In many instances, the impurities take the form of various organic and inorganic ionic species. Thus, for example, anions such as sulfite and sulfate may be present which interfere somewhat in the performance of the ether sulfonate for its chosen utility. In other cases, diionic organic impurities may be present, such as disulfonates and disulfinates. In still other instances, both inorganic and organic impurities of this type or others are present.
As just one example of the above it has been determined that a chemical to be useful as an additive in promoting oil recovery must have the proper hydrophobic-hydrophilic ratio or HLB balance. Undue amounts of ionic impurities will destroy such desired balance leading to lesser activity of the active ingredient.
It would therefore be a substantial advance in the art if a method were known of purifying organic ether sulfonates by freeing them of deleterious ionic species of the organic or inorganic type such as those mentioned above or others.
It is therefore a principal object of this invention to provide a process for the purification of organic ether sulfonates whereupon said sulfonates are freed of injurious ionic impurities which tend to interfere with the ultimate performance of the ether sulfonate product.
A specific object of the invention is to provide the just mentioned purification method which can be carried out simply, and economically without resort to sophisticated equipment and multi-steps. The above-mentioned objects and advantages of the present invention will become apparent as the invention is more thoroughly set out hereinafter.